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Blood biomarkers for Alzheimer disease across ethnoracial groups and healthcare settings: a systematic review and meta-analysis
Ma X, Hansra GK, Jayasena T, Crawford JD, Poljak A, Sachdev PS.. medRxiv, 2026-05-18
Topic: Amyloid, tau and blood-test diagnosis
Blood-based biomarkers could transform Alzheimer disease (AD) detection by enabling scalable, less invasive assessment of underlying pathology, yet their applicability across globally diverse populations remains uncertain. We systematically reviewed 168 publications comprising 139 independent cohorts from Asia, Europe, North America, South America, Africa and Oceania. Random-effects meta-analyses pooled log-transformed ratios of mean biomarker concentrations for AD versus cognitively unimpaired individuals, mild cognitive impairment versus cognitively unimpaired individuals, and amyloid-β PET-positive versus amyloid-β PET-negative individuals. p-tau217, p-tau181 and glial fibrillary acidic protein showed the largest and most consistent group differences.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Ma, X., Hansra, G. K., Jayasena, T., Crawford, J. D., Poljak, A., & Sachdev, P. S. (2026). Blood biomarkers for Alzheimer disease across ethnoracial groups and healthcare settings: a systematic review and meta-analysis. medRxiv. https://doi.org/10.64898/2026.05.14.26353162
Vancouver
Ma X, Hansra GK, Jayasena T, Crawford JD, Poljak A, Sachdev PS. Blood biomarkers for Alzheimer disease across ethnoracial groups and healthcare settings: a systematic review and meta-analysis. medRxiv. 2026. doi:10.64898/2026.05.14.26353162.
BibTeX
@article{ma2026-de7bbfdf,
author = {Ma, X. and Hansra, G. K. and Jayasena, T. and Crawford, J. D. and Poljak, A. and Sachdev, P. S.},
title = {{Blood biomarkers for Alzheimer disease across ethnoracial groups and healthcare settings: a systematic review and meta-analysis}},
journal = {medRxiv},
year = {2026},
doi = {10.64898/2026.05.14.26353162},
url = {https://doi.org/10.64898/2026.05.14.26353162}
}
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Key findings
- We systematically reviewed 168 publications comprising 139 independent cohorts from Asia, Europe, North America, South America, Africa and Oceania.
- Random-effects meta-analyses pooled log-transformed ratios of mean biomarker concentrations for AD versus cognitively unimpaired individuals, mild cognitive impairment versus cognitively unimpaired individuals, and amyloid-β PET-positive versus amyloid-β PET-negative individuals. p-tau217, p-tau181 and glial fibrillary acidic protein showed the largest and most consistent group differences.
- In clinically defined comparisons, p-tau181 separation in mild cognitive impairment was lower in predominantly Asian than White cohorts, whereas glial fibrillary acidic protein separation in AD was higher in predominantly Asian cohorts.
- No significant between-population differences were observed in amyloid-defined comparisons.
Why it matters
This meta-analysis of 168 publications found that p-tau217, p-tau181 and glial fibrillary acidic protein showed the largest and most consistent differences across ethnoracial groups and healthcare settings. It supports blood biomarkers as a scalable, less invasive way to detect Alzheimer pathology, but says nothing about treating, curing or preventing it.
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Study details
- Study designmeta-analysis
- Evidence strengthHigh
How this study scored 16/100
Preprint — not yet peer-reviewed. It scored 37 on the same rubric, but non-peer-reviewed sources are capped at 16, so it shows as 16. Scored zero for sample size, effect reported and studied in people because the record does not state it. We have no data on impact for its field and year, so that was left out: it earned 35 of the 94 points we could judge it on, which is 37 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 2 / 10 | Tier 4 — not a peer-reviewed journal (medRxiv) |
| Journal's citation record | 0 / 4 | Not a journal article, so the journal's record does not count |
| Study design | 12 / 12 | A meta-analysis pooling many studies |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 4 / 10 | Preprint — not yet peer-reviewed. Hosted on a preprint server. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomized / blinded | 0 / 2 | A review of other studies — randomization is not credited here |
| Times cited | 0 / 7 | Cited 0 times (OpenAlex, 2026-10-10) |
| Citations per year | 0 / 5 | 0.0 citations a year over 2 year(s) since 2026 |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 0 / 4 | Cited 0 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Perminder Singh Sachdev: h-index 147 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | UNSW Sydney: institution h-index 1,101 (OpenAlex) |
| Multicenter collaboration | 1 / 3 | OpenAlex lists 3 institution(s) in 1 country |
| Indexed in PubMed | 1 / 2 | Not in PubMed, but has a DOI |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 35 / 94 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 35 of the 94 points we could judge it on is 37 out of 100. |
| Total | 37 / 100 | Capped to 16 because this is not a peer-reviewed article. |
What each of these 20 components measures, and what this score is not →
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